Platen driving device in an electrophotographic copying machine

ABSTRACT

Apparatus for driving a platen in an electrophotographic copying machine including a platen, a drive roller in friction contact with the bottom of the platen, a platen support means, power means for rotating the drive roller to move the platen in a predetermined direction in the horizontal plane, and depressing means for depressing the platen onto the drive roller to thereby prevent vertical movement of the platen during movement of the platen in the predetermined direction.

United States Patent 91 Yamamoto [54] PLATEN DRIVING DEVICE IN AN ELECTROPHOTOGRAPHIC COPYING MACHINE [30] Foreign Application Priority Data 1451 June 5, 1973 [56] References Cited UNITED STATES PATENTS 2,588,244 '6/1971 'Murgas ..355/8 Primary Examiner-John M. l-Ioran Assistant Examiner-Richard A. Wintercorn Attorney-Gerald J. Ferguson, J r.

[5 7] ABSTRACT Apparatus for driving a platen in an electrophotographic copying machine including a platen, a drive Dec. 14, 1970 Japan ..-.....'.45/123929 roller in friction Contact with the'bbttom of the p a platen support means, power means for rotating the drive roller to move the platen in a predetermined [52] U.S. Cl, 355/3 355 1 355/25 direction in the horizontal plane, and depressing i 1 55 355/75 means for depressing the platen onto the drive roller 51 Int. Cl. ..G03b 27/48, 0031, 27/50 to thereby Prevent vertical movement o the platen [581 Field ofSearch "355/8 11 25 so during mvemem 0f the Plate" in the predetermined direction. v

v l Claim,'6 Drawing Figures 38/ I I K II To n .l

1 ,.r 2 Q 1* CL Lf l PMENIEDJUN 5 ms (.3, 737 223 SHEET 10F 2 FIG. I 2. |o Q1 I 0 c L C B FIG. 2

PATENIEDJUN 51m 3.731.223

' SHEEI 20F 2 FIG 5 PLATEN DRIVING DEVICE IN AN ELECTROPHOTOGRAPHIC COPYING MACHINE BACKGROUND OF THE INVENTION This invention relates to a platen driving device in an electrophotographic copying machine and in particular SUMMARY OF THE INVENTION Thus, it is a primary object of this invention to provide improved apparatus for driving a platen in an electrophotographic copying machine which is easily assembled,"adjusted,jand repaired.

A further object of this invention is to provide a platen driving apparatus of the above type which is compact thereby using a minimum amount of space in the electrophotographic copying machine.

Other objects and advantages of this invention will become apparent upon reading the appended claims-in conjunction with the following detailed'description and the attached drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a schematic side view of an embodiment of a platen driving device in accordance with the invention. i FIG. 2 is a partial plan view thereof.

FIGS. 3 and 4 are respective partial sectional plan views of the device along the lines 3--3 and 4 -4 in FIG. 1. v V i FIGS. 5 and 6 are exploded and assembled perspective views of the platen.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the figures of the drawing, like reference numerals refer to like parts.

Referring to FIGS. 5 and 6, there is shown a platen 10 comprising frames bl, b2, b3 and 124 disposed around glass a. As can best be seen in FIGS. 1,3, and 4 platen 10 is supported by a pair of platen supporting rollers 12 and 12' and a pair of rubber platen drive rollers l3 and 13'. Also as can be seen in FIGS. 4 and 5, platen 10 is urged downwardly onto platen drive roller 13 by a depressing roller 14 disposed in a groove 38 provided in the side of frame b2 of platen 10. Referring V The support rollers Hand 12' are respectively disposed'in guide rails 18 and 18' which are respectively mounted on the frames '15 and 15' so as to roll in the guide rails 18 and 18' whenever movement of the platen 10 occurs.

Also a guide roller 20 mounted on a drive shaft 19 is disposed in a groove 20' provided on the lower surface of the frame b2 of the platen 10 at the front of the platen as shown in FIG. 4. Thus, zig-zag movement of theplaten is eliminated. v

The platen drive rollers l3 and 13' and the guide roller 20 are fixedly mounted on the drive shaft 19, which is supported by the frames 15 and 15', as can be seen in FIG. 4. A gear 21 is mounted on one end of drive shaft 19, the gear 21 being engaged with a clutch gear 22 which in turn is engaged with a clutch gear 23. The clutch gears 22 and23 are operated by electromagnetic clutches 24 and 25, respectively, and when the clutches 24 and 25 are operated, the gear 22 or 23 becomes integral to a shaft 26 or 27, respectively. Pulleys 28 and 29 are mounted onto shafts 26 and 27, respectively. The pulleys are connected by belt 32 to pulley 31 which is mounted on drum shaft 30 of drum 33.

An actuator 34 (see FIG. '2) is provided at the side surface of the platen 10, actuator 34 cooperating'with microswitches 35 and 35 as will be brought out hereinafter. i

- A groove 37 is provided on the opposite side surface to the groove 38 for depressing roller 14 of the platen 10, the groove 37 having a recess 37 disposed at one end thereof, see FIG. 5. A pin 39 is provided in groove 37, one end of the pin being supported in frame 15,

while the other end is attached to a lever 41 biased by a spring 40 connected at the bottom thereof to frame 15 so as to urge the platen l0 downwardly by a weak force so that platen 10 is maintained stationary when drive rollers 13 and 13"are not actuated. The spring 40 is so selected-that the downward urging force of pin 39 becomes less than thefrictional force of the drive rollers 13 and 13' when they are'actuated. Thus, the platen l0 advances to overcome the force of pin 39 by driving the drive rollers 13 andl3'. A stop 32 (see FIG. 2) is also provided. I v

In operation, when drum shaft 30 together with drum 33 are operated, the clutch shafts 26 and27 will rotate in the same direction, but the drive shaft 19 will not rotate at this time. When the clutch 24 is operated by a proper signal from the electrophotographic system, the

gear 22 transmits the rotation of shaft 26 through gear 21 to drive shaft 19, and accordingly the drive roller '13 rotates so that the platen l0 disposed between the drive rollers 13 and 13' and depressing roller 14 and pin 39 moves. The platen 10 moves smoothly under the control of guide roller 20 and the supporting rollers 12 and 12' so that an original B (see FIG. 1) is exposed to an exposure lamp C so that the imageis projected onto the drum 33 through a proper optical system (not shown). When the platen 10 moves to :the point that the actuator 34 contacts and'switches the microswit ch 35, the clutch 14 is disengaged by the signal of switch 35 and the clutch 25 is operated so that the rotation of drive shaft l9 reverses through the gears 21, 22 and 23.

When the platen 10 again returns to the original position so as to operate the micros witch 36, the clutch 25 I is disengaged by the signal so as to stop the platen 10 and maintain it in the stationary position until the next pin 39 falls in the recess'37 of the groove 37. Of

course, means (not shown) would be provided to remove pin 39 from recess 37 prior to the next image ex-' platen supporting rollers 12 and 12' and the'drive rollers 13 and 13' while at the same time theplaten is urged by the depressing roller 4 and pin 39 onto the drive rollers 13 and'l3, the structure becomes simple and the assembly, adjustment and repair are readily facilitated.

Numerous modifications of the invention will become apparent to one of ordinary skill in the art upon reading the foregoing disclosure. During such a reading it will be evident that this invention provides a unique platen driving device for accomplishing the objects and advantages herein stated.

What is claimed is:

1. Apparatus for driving a platen in an electrophotographic copying machine comprising a platen;

at least one drive roller in friction contact with the bottom of said platen;

at least one platen support roller disposed at the bottom thereof;

power means for rotating said drive roller to move said platen in a predetermined direction in the horizontal plane;

at least one depressing roller for depressing said platen onto said drive roller to thereby prevent vertical movementof said platen during movement of said platen in said predetermined direction;

a first groove disposed along the bottom length of said platen, said first groove being cooperatively engaged with a guide roller mounted on a first shaft upon'which said drive roller is mounted;

a second groove disposed along one side of said platen; said said second groove being cooperatively engaged with said one depressingroller which is biased with a depressing means to thereby press said platen onto said drive roller, and

a third groove disposed along the opposite side to said one side, which prevents said platen from moving other than along the predetermined direction in cooperation with a pin slideably disposed in said third groove and downwardly biased to said platen, said third groove having a gradually raised portion with which said platen is gradually stopped. 

1. Apparatus for driving a platen in an electrophotographic copying machine comprising a platen; at least one drive roller in friction contact with the bottom of said platen; at least one platen support roller disposed at the bottom thereof; power means for rotating said drive roller to move said platen in a predetermined direction in the horizontal plane; at least one depressing roller for depressing said platen onto said drive roller to thereby prevent vertical movement of said platen during movement of said platen in said predetermined direction; a first groove disposed along the bottom length of said platen, said first groove being cooperatively engaged with a guide roller mounted on a first shaft upon which said drive roller is mounted; a second groove disposed along one side of said platen, said said second groove being cooperatively engaged with said one depressing roller which is biased with a depressing means to thereby press said platen onto said drive roller, and a third groove disposed along the opposite side to said one side, which prevents said platen from moving other than along the predetermined direction in cooperation with a pin slideably disposed in said third groove and downwardly biased to said platen, said third groove having a gradually raised portion with which said platen is gradually stopped. 